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Grilled Flat Iron Steak Tostada with Coconut-Chili Mayo and Guacamole Recipe

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Have you been craving the bold flavor and tenderness of a juicy flat iron steak? How about a dish featuring a crunchy tostada with a sweet and savory flair? With the perfect combination of spice, tender flat iron steak, and sweetness, this dish makes an ideal lunch, crowd-pleasing appetizer, or side dish!

Why We Love This Flat Iron Steak Tostada Recipe

Recreating a Mexican-style dish can seem like a lot of work, but it’s super easy! This delectable recipe features bold, tender flat iron steak with a crunchy tostada topped with pickled onions, sweet coconut-chili mayo, savory grilled corn, and creamy guacamole. After one bite, your taste buds will thank you!

Tools You’ll Need Before You Start

  • 1 Small Bowl
  • 1 Medium Sauce Pan
  • 3 Medium Mixing Bowls
  • Food Processor
  • 1 Knife
  • 1 Potato Masher
  • 1 Spoon
  • 1 Large Resealable Bag

How to Make Flat Iron Steak Tostada

Any perfectly aged steak from Omaha Steaks will complement the rich flavors of this recipe, but my favorite steak cut for this dish is the Omaha Steak Flat Iron Steak. This popular steak is the second tenderest steak behind our filet mignon and has a juicy, robust, beefy flavor. Each flat iron is aged at least 28 days to maximize tenderness and hand-carved by our master butchers for a perfect steak! Every bite of this tostada is guaranteed to please.

1. Prepare the Pickled Red Onions

Pickled red onions are simple to prepare and deliver a sweet, tangy, and aromatic flavor. They are a tasty addition to our flat iron steak tostada! To pickle the red onions, add acidic apple cider vinegar, sweet agave nectar or honey, clean-tasting kosher salt, and spicy crushed red pepper in a medium saucepan, bring to a boil, and simmer to create the pickling liquid. Place mildred onions in a small bowl, pour the/your hot pickling liquid over the onions, cover with plastic wrap, and let sit for 10 minutes. Bring the pickling liquid to room temperature and store in the refrigerator for later use. 

2. Let’s Whip Up Some Coconut-Chili Mayo

This coconut-chili mayo is the perfect addition to the tostadas’ toppings! In a medium mixing bowl, add creamy mayonnaise, nutty unsweetened coconut milk, fresh lime juice, acidic apple cider vinegar, floral lemongrass paste, tangy sriracha, salt, and pepper, whisking until well incorporated. Season to taste with salt and pepper.

3. Create the Perfect Steak Marinade

This steak marinade is simple to whip up and delivers excellent, complex flavors that complement the flat iron steaks! To make this marinade, add your olive oil base, fresh cilantro, citrusy Italian parsley, rough-chopped green onion, tart lime juice, slightly sweet balsamic vinegar, sweet brown sugar, extra-spicy serrano pepper, clean-tasting kosher salt, aromatic black pepper, pungent garlic cloves, and warm crushed red pepper in a food processor, blending until well incorporated, and set off to the side until your steaks are ready to be marinated. 

4. Get Corny With It

This grilled corn will elevate your dish! Toss the fresh yellow sweet corn in olive oil until well coated, and add Tajín Clásico seasoning to the bowl and toss again until the corn is coated with the seasoning. Grill the corn at 450 degrees Fahrenheit for 6 minutes until the corn is golden brown and charred. Remove the corn from the grill and use a sharp knife to remove kernels; keep warm until it’s time to serve.

5. Holy Guacamole, You’re Going to Love This

No tostada recipe is complete without some creamy and flavorful guacamole! Placeripe Hass avocados, diced red onion, minced serrano pepper, fresh cilantro, and tart lime juice in a medium mixing bowl, add a pinch of salt and pepper, and use a potato masher to mash avocados to desired consistency. Then, use a spoon to mix all ingredients until well incorporated and season to taste with salt and pepper. 

5. Make No Mis-Steak, This Steak is Great 

To grill up a tender flat iron steak for this dish, get started the night before by thawing your Omaha Steaks Flat Iron Steaksin the refrigerator or with our convenient quick-thaw method. Once thawed, pat steaks dry and season each flat iron steak liberally with salt and pepper. Season with savory cumin and sweet paprika, allow them to come to room temperature on the counter for about 10 minutes, and then place the seasoned steaks in a large, resealable bag. Next, pour the steak marinade over the steaks and marinate them in the refrigerator overnight or for at least four hours. 

Let’s get the grill ready! Pre-heat the grill to 450 degrees Fahrenheit direct heat and lightly oil the grill grates with grapeseed oil. Remove the steaks from the refrigerator and bring to room temperature over 20 to 25 minutes. Now it’s time to grill! Place the steaks on the grill for about 4 minutes on each side for medium-rare doneness; refer to our helpful Omaha Steaks steak doneness guide for different desired cooking doneness. Let the steaks rest for six minutes and cut into 1/2″ slices. 

Now that all of your different components are ready, it’s time to assemble a crispy tostada! First, place a thin layer of guacamole on a yellow corn tostada, followed by 4 to 5 steak slices. Then, top with pickled onions, grilled corn, a drizzle of coconut-chili mayo, and fresh cilantro. Lastly, finish with Tajín Clásico seasoning on top and enjoy!

 

Grilled Flat Iron Steak Tostada with Coconut-Chili Mayo and Guacamole

This delectable Mexican-style recipe features bold, tender flat iron steak with a crunchy tostada topped with pickled onions, sweet coconut-chili mayo, savory grilled corn, and creamy guacamole.
Prep Time20 mins
Cook Time15 mins
Total Time35 mins
Course: Main Course
Cuisine: Mexican
Keyword: Flat Iron Tostada
Servings: 8 servings
Author: Chef David Rose

Ingredients

Pickled Red Onion

  • 1 medium red onion, cut in half, sliced thinly
  • 1 cup apple cider vinegar
  • 3 tablespoons agave nectar or honey
  • 1/2 teaspoon kosher salt
  • 1/4 teaspoon crushed red pepper

Coconut-Chili Mayo

  • 1 cup mayonnaise
  • 1/4 cup coconut milk, unsweetened
  • 1 tablespoon fresh lime juice
  • 1 teaspoon apple cider vinegar
  • 1 teaspoon lemongrass paste
  • 2 teaspoons sriracha
  • Salt
  • Pepper

Steak Marinade

  • 1 cup olive oil
  • 1/2 cup packed cilantro
  • 1/2 cup packed Italian parsley
  • 1/2 cup rough-chopped green onion
  • Juice of 1 small lime
  • 3 tablespoons balsamic vinegar
  • 2 tablespoons brown sugar
  • 1 teaspoon serrano pepper, de-seeded, minced
  • 1 teaspoon kosher salt
  • 1/2 teaspoon black pepper
  • 3 garlic cloves
  • 1 pinch crushed red pepper

Grilled Corn

  • 4 ears fresh yellow sweet corn, shucked, washed, and dried
  • 1/4 cup olive oil
  • 2 teaspoons Tajín Clásico seasoning

Guacamole

  • 2 large ripe Hass avocados, pitted, meat removed
  • 1/4 cup red onion, small diced
  • 1/2 of a small Serrano pepper, minced
  • 2 tablespoons cilantro, freshly chopped
  • Juice of 1 medium lime
  • Salt
  • Pepper

Flat Iron Steak

  • 4 6 oz. Omaha Steaks Flat Iron Steaks
  • Steak marinade
  • Guacamole
  • Grilled corn
  • Coconut-chili mayonnaise
  • Pickled red onion
  • Salt
  • Pepper
  • 2 teaspoons cumin, divided
  • 2 teaspoons paprika, divided
  • 8 yellow corn tostadas
  • Tajín Clásico seasoning, for garnish
  • 4 tablespoons cilantro, freshly chopped, for garnish

Instructions

Pickled Red Onion

  • Place all ingredients except red onions in a medium saucepan, bring to a boil, and simmer for 2 minutes on medium heat to create pickling liquid.
  • Place red onions in a small bowl; pour hot pickling liquid over onions, cover with plastic wrap, and let sit for 10 minutes.
  • Allow to cool to room temperature before storing in refrigerator for later use.

Coconut-Chili Mayo

  • Put all ingredients in a medium mixing bowl, add a pinch of salt and pepper, and whisk until well incorporated. Season to taste with salt and pepper.
  • Steak Marinade
  • Place all ingredients in a food processor and blend until well-incorporated, set aside.

Grilled Corn

  • Toss corn in olive oil in a medium bowl until well coated; add Tajín Clásico to bowl and toss until coated with seasoning.
  • Grill corn on 450 degree Fahrenheit direct heat for about 6 minutes total, turning halfway through, until corn is golden brown and slightly charred.
  • Remove corn from grill and use a sharp knife to remove kernels; keep warm until serving.

Guacamole

  • Place all ingredients in a medium mixing bowl, add a pinch of salt and pepper, and use a potato masher to mash avocados to desired consistency.
  • Use a spoon to mix all ingredients until well incorporated; season to taste with salt and pepper.

Flat Iron Steak

  • Pat steaks dry, season liberally with salt and pepper, and equally season with cumin and paprika; let sit on counter for 10 minutes and then place seasoned steaks in a large resealable bag.
  • Pour steak marinade over steaks and marinade in refrigerator overnight or at least 4 hours.
  • Pre-heat grill to 450 degrees Fahrenheit direct heat and lightly oil grill grates with grapeseed oil.
  • Remove steaks from refrigerator and bring to room temperature over 20 to 25 minutes.
  • Grill steaks for about 4 minutes on each side for medium-rare doneness; for different desired cooking doneness, refer to Omaha Steaks doneness guide. Rest steaks for 6 minutes and cut into 1/2” slices.
  • To assemble tostadas, place a thin layer of guacamole on base, followed by 4 to 5 steak slices, about one teaspoon of pickled onions, about 2 tablespoons of grilled corn, a drizzle of coconut-chili mayo, and about a teaspoon of cilantro and lightly finish with sprinkling of Tajín Clásico on top.

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